This invention relates to switch devices having liquid level control capability and more particularly to those used to control the level of carbonated liquid contained in a vessel or storage tank associated with ordinary liquid vending machines.
Previously, vending machines of the aforementioned type have contained vessels for storage of carbonated liquid which when empty would necessitate replacement of the vessel. Because of the difficulty in changing the vessel, it became desirable to make the vessel or storage tank replenishable, thereby obviating the necessity of replacing the vessel when empty. Concurrent with this desired development, it was necessary to have a sensing device adapted to determine the level of carbonated fluid or the like located within the replenishable vessel. Probe devices were developed in which an annular magnet located in a float element traversed vertically with the float element along a probe thereby activating or deactivating a reed switch of the conventional type located within the probe. Thus the level of fluid in the vessel was monitored and appropriate automatic filling apparatus activated when necessary.
Similarly, it became desirable to have a liquid level control device able to maintain an extended fluid inlet cycle due to the dilaterious effect upon pump motors caused by rapid on-off operation, occasioned by small changes in the liquid level within the vessel and associated vertical traversal of the annular magnet. This has previously been accomplished, as in the U.S. Pat. No. 3,408,053, by an internally disposed magnetic sleeve element which caused the latch type components of a conventional reed switch to maintain a juxtaposed relationship longer than would occur under normal activation by the position of an annular ceramic magnet located in the float element.